From the ABC:

Scientists reveal mystery word on Declaration of Independence

Scientists at the United States Library of Congress have revealed the moment when Thomas Jefferson altered the Declaration of Independence to set the course of American history.

The discovery was made public to mark the Fourth of July, when the US celebrates Independence Day.

The blur of ink on the 1776 document has long puzzled historians.

Thomas Jefferson, the architect of the Declaration of Independence had obviously changed his mind about something, but until now nobody realised the significance of his thinking.

By examining the draft and the different wave lengths of light – a process known as hyper-spectral imaging – scientists discovered his original word was, subjects.

But in a flash of inspiration while the ink was still wet he wiped it, and wrote citizens instead.

That was the moment according to historians that redefined the American colonists.

– BBC